JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<body>
    <table style="width: 600px;">
<tr>
    <td>
        <select>
            <option>Merchant</option>
            <option value="1,2,3,4">1</option>
            <option value="5,6,7,8">2</option>
        </select>
    </td>
    <td><input value="Value"></td>
    <td><input value="Price"></td>
    <td onclick="roi_calc(this);"> R.O.I </td>
</tr>

</table>
</body>
</html>

JavaScript

function roi_calc(e) {
    //alert ('works');
    var merchant_option = $(e).prev('td').prev('td').prev('td').find('select').val();
    if (merchant_option != 'Merchant') {
        var value_input = $(e).prev('td').prev('td').find('input').val();
        //alert (value_input);
        if ((value_input != '') && (value_input != 'Value')) {
            var price_input = $(e).prev('td').find('input').val();
            if ((price_input != '') && (price_input != 'Price')) {
                //var price_arr = new Array();
                //price_arr = $(e).prev('td').find('input').val();
                //alert (price_arr[1]);
                alert('Merchant value = ' + merchant_option);
                //var price_arr = new Array();
                var price_arr = price_input.split(',', 3);
                alert(price_arr);
                alert(price_arr[0]); //working
                alert(price_arr[1]); //not working - undefined
                alert(price_arr[2]); //not working - undefined
                //$(e).html(
            }
            else {
                alert('Price must be entered.');
            }
        }
        else {
            alert('Value must be entered.');
        }
    }
    else {
        alert('Merchant must be selected');
    }
    //alert (row_option);
}